Apparatus for removing or inserting a piston in reciprocating engines

ABSTRACT

A device to assist the mounting and dismounting of a piston through the crankshaft side of the cylinder of a reciprocating engine. The device mounts upon the crankshaft and is adapted to receive the piston thereon. The device includes means to center the piston so that it is axially aligned with the cylinder and to displace the piston radially of the crankshaft into and out of engagement with the cylinder. When the piston is engaged within the cylinder, the device may be removed from the crankshaft to permit connection of the usual connecting rod from the piston to the crankshaft.

United States Patent 11 1 1111 3,793,718 Okazaki 1 Feb. 26, 1974 APPARATUS FOR REMOVING 0R 1,572,135 2/19261 Gillis 29/222 {NSERTING A PISTON [N RECIPROCATING 2,421,276 5/1947 Lotz 29/252 ENGINES Inventor: Takeo Okazaki, Tokyo, Japan Assignees: Mitsui Shipbuilding and Engineering Company Ltd.; Japan Ships Machinery Development Association,

both of Tokyo, Japan; part interest to each Filed: Nov. 3, 1972 Appl. No.: 303,310

Foreign Application Priority Data Nov. 8, 1971 Japan 46-88826 References Cited UNITED STATES PATENTS 12/1924 Maas 29/256 Primary Examiner-Othell M. Simpson Attorney, Agent, or Firm-Howson and Howson,

He ry 11,-. l??? [57] ABSTRACT A device to assist the mounting and dismounting of a piston through the crankshaft side of the cylinder of a reciprocating engine. The device mounts upon the crankshaft and is adapted to receive the piston thereon. The device includes means to center the piston so that it is axially aligned with the cylinder and to displace the piston radially of the crankshaft into and out of engagement with the cylinder. When the piston is engagedwithin the cylinder, the device may be removed from the crankshaft to permit connection of the usual connecting rod from the piston to the crankshaft.

1 Claim, Drawing Figures APPARATUS FOR REMOVING OR INSERTING A PISTON IN RECIPROCATING ENGINES The present invention relates to apparatus for removing or inserting a piston in reciprocating engine such as internal combustion engine.

For the purpose of inspection of an engine such as internal combustion engine, the usual practice is to remove the piston and to do this it is necessary to remove the cylinder head cover and then draw the piston upwardly. In order to remove the cylinder head, certain preparatory work must be done, such as the separation of the cylinder head piping, separation of valve actuating mechanism and releasing of cylinder head fastening bolts. All this requires much labour and time.

Therefore, an object of the present invention is to' overcome the above conventional drawbacks by an apparatus which enable to the piston to be removed from the side of the crankcase with a minimum of work and time.

The apparatus according to the present invention comprises means for lifting a piston separated from the connecting rod or a piston separated from the connecting rod near at the lower end of the piston remaining the small end and means for centering the piston to the center of the cylinder liner.

In the drawings,

FIG. 1 is a perspective view of an apparatus in accordance with the present invention;

FIG. 2 is a sectional side view showing a condition before insertion of piston;

FIG. 3 is a sectional view taken along a line 3 3 of FIG. 2;

FIG. 4 is a sectional view taken along a line 4 4 of FIG. 2; and

FIG. 5 is a sectional view showing a device for holding a piston in a cylinder-liner.

Referring to the drawings, a pair of balance weights 11 are fixed to a crankshaft l0, and recesses 12 and 13 are formed in the opposite sides of the balance weights for receiving an apparatus according to the present invention. The lifting apparatus according to the present invention is generally designated by a numeral 14 and consists of a supporting member 15 engageable with the recesses 12 and 13, a lifting plate 16 and a pair of centering devices 17 and 18. The lifting plate 16 is engaged with a pair of feed screws 19 rotatably supported on the supporting member 15. The feed screws are rotated by an oil motor 20 through a shaft 21 and bevel gears 22, 23, 22a and 23a to feed the lifting plate 16. The centering devices 17 and 18 are connected to each other by oil cylinders 24 and 25 and also connected to the side wall portion of the supportingmember by oil cylinders 26 and 27.

The operation of insertion of a piston 28 will now be described. The piston 28 is separated from the connecting rod near the piston and put on the lifting plate 16 at the outside of the engine. This lifting apparatus 14 is inserted from the opening of the crankcase, and the supporting member 15 is received in the recesses 12 and 13 of the balance weights 11 as shown in FIGS. 2 and 3. The crankshaft is rotated so as to align the center of the piston with the center of the cylinder liner 30. Then the pressure oil cylinders 26, 27 are operated, the centering devices 17, 18 are-raised to press upper surfaces 31 to the under surface 32 of the cylinder liner 30. By operating the oil cylinders 24, 25 thereafter, the centering devices 17, 18 are contracted until the interior faces 33 thereof engage with the exterior surface 34 of the cylinder linerJAt this time, the interior faces of the centering devices 17, 18 contact with the circumference of the piston, thereby the center of the upper surface 35 of the piston and the center of the centering devices 17, 18 are alined with the center of the cylinder liner 30.

By two sensors 36 comprising a differential transformer fixed in the centering devices 17, 18, the inclination of piston 28and its direction are detected, of which signal operates an oil supply device through an operation circuit not shown in the drawing, thereby supplying or discharging the pressure oil to oil cylinders 37, 37a, 38, 38a, 39, 39a provided, in the supporting member 15 shown in .FIG. 4. Each cylinder piston contacts with the wall of recesses 12,13 of balance weights, and the supporting member is shifted depending on the projecting or retracting of the piston. The center of the under surface of the piston 28 is thereby shifted to align with the center of the cylinder liner 30.

Thereafter the oil motor 20 is operated so that two screws 19 are rotated through bevel gears 22, 22a, 23, 23a, thereby the lifting plate 16 is raised and the piston 28 is inserted into the cylinder liner 30. After the insertion of the piston, a piston rod 43 of a oil cylinder 42 provided on a framework 41 as shown in FIG. 5 is inserted into holes provided in the cylinder liner 30 and piston 28 so that the piston 28 is held by the piston rod 43. The lifting plate 16 is then lowered to separate the centering devices 17 18 from the cylinder liner, the crankshaft 10 is rotated to the suitable position, where the lifting apparatus 14 is removed from the balance weights and taken out of the engine. The piston is thereafter connected to the connecting rod, and the piston rod 43 of oil cylinder 42 is retracted, thereby completing the piston inserting operation.

The operation for removing the piston is performed in the similar manner to theabove manner. The piston 28 is held by the piston rod 43 thereafter the center of the centering devices 17, 18 is aligned with that of a cylinder liner 30, then supporting the piston by the lifting plate 16. Thereafter the piston rod 43 is released and lifting plate 16 is lowered, thereby the piston 28 is lowered.

From the foregoing it will be understood that according to the present invention removing and inserting works of the piston are easily and quickly performed without preparatory work such as the separation of the cylinder head.

What is claimed is:

1. An apparatus for removing or inserting a piston in reciprocating engines comprising a supporting member removably mounted on a crankshaft, a lifting plate pro vided on said supporting member mounted movably to be moved in the radial direction of the crankshaft, centering devices mounted on said supporting member for aligning the center of the piston on the lifting plate with the center. of a cylinder liner, a drive mechanism for moving the lifting plate, means for operating the cen- 

1. An apparatus for removing or inserting a piston in reciprocating engines comprising a supporting member removably mounted on a crankshaft, a lifting plate provided on said supporting member mounted movably to be moved in the radial direction of the crankshaft, centering devices mounted on said supporting member for aligning the center of the piston on the lifting plate with the center of a cylinder liner, a drive mechanism for moving the lifting plate, means for operating the centering devices, and means for holding the piston in the cylinder liner. 